1. Field of the Invention
The present invention relates to a portable terminal. More particularly, the present invention relates to a speaker apparatus that can be embedded in a portable terminal, the speaker apparatus having a slim construction and being suitable for implementing multimedia functions.
2. Description of the Related Art
In general, the term “portable terminal” refers to an apparatus for performing mobile communication between users, or between a user and a service provider, through a mobile communication base station. With a portable terminal, various types of service content, including mobile banking, watching TV, on-line games, audio-on-demand as well as voice calls and sending text messages, can be performed.
Such portable terminals are classified into several different types depending on their physical structures. For example, bar-type terminals have one housing, at which an input/output device, such as a communication circuit, a transmitting unit, a receiving unit, etc., is installed. A flip-type terminal has a bar-type body, on which a flip cover is installed. And a folder-type terminal has a pair of housings that rotate so as to be opened/closed and includes input/output devices arranged on each housing. Sliding-type terminals have recently appeared and have become popular because they increase the convenience and portability of mobile terminals, and satisfy various demands of a user together with folder-type terminals.
In an early stage of system development, communication services performed using such portable terminals was limited to conventional communication services such as voice calls, sending short text message, etc. However, communication services supported by such portable terminals has recently included multimedia services such as games, music, the sending of moving picture files, online games, etc. as well as digital multimedia broadcasting (hereinafter, referred to as DMB).
According to the recent tendency of recognizing multimedia capabilities of a portable terminal as an important function, there is a high level of effort in improving the output sound of a portable terminal. An example of such an effort is Korean Patent No. 594,064 issued on Jun. 24, 2006 (and its associated US Pre-Grant Publication No. 2004/0097258 published on May 20, 2004, the entire disclosures of both of which are hereby incorporated by reference) which discloses a portable terminal including a speaker apparatus supplying stereo sound. The disclosed portable terminal has a structure where a speaker apparatus is installed at a hinge-assembled part of a folder-type terminal.
Meanwhile, if portability of a terminal is considered, it is desirable for the size of the portable terminal to be reduced. However, since various multimedia functions are now provided by the portable terminal, a sufficient size of a display apparatus has to be secured so that the effort in size-reduction of the portable terminal has been focused on reducing a thickness of the portable terminal. Therefore, it is not possible to secure space within a hinge-assembled part of the portable terminal at which a speaker apparatus can be installed as described above.
Furthermore, in order to enjoy multimedia services, sufficient sound volume has to be secured and be uniformly output within an audio frequency range (20 Hz˜20 kHz). However, it is much more difficult to secure such conditions of output sound in a portable terminal of a slim construction. That is, resonance space has to be secured within the speaker apparatus in order to obtain sufficient sound volume and uniform output of sound, but securing such resonance space is difficult in a portable terminal of a slim construction. Furthermore, a speaker unit, which is manufactured as a separate component by a speaker manufacturer, is supplied to the portable terminal manufacturers. As a result, there is an increasing difficulty in that space for installation of a pre-manufactured speaker unit as well as resonance space has to be secured when manufacturing portable terminals.
Also, the structure of a speaker unit, which allows the volume of received bell sounds, etc. to be secured in a state of a folder-type terminal being folded, has been suggested. However, it is also difficult to secure sufficient resonance space within the structure of the speaker unit so that a separate resonance case receiving the speaker unit has to be installed within the portable terminal. Furthermore, although it is possible to secure resonance space in such a manner that a speaker unit is received in a separate resonance case and the separate resonance case is installed in the portable terminal, it is difficult to secure space for installation of the speaker module having such a structure within a portable terminal having a slim construction.